"Exercicio 1.2"
"Notacao infixa:"
"5 + 4 + (2 - (3 - (6 + 4/5)))"
"-----------------------------"
"       3(6 - 2)(2 - 7)"
(/ (+ 5
      4
      (- 2 (- 3 (+ 6 (/ 4 5)))))
   (* 3
      (- 6 2)
      (- 2 7)))